There have been several studies concerning the neural basis of walking; these studies have primarily used cats, crustaceans and insects. The most fully understood is the cockroach walking system because: 1) patterns of innervation are fairly well established; 2) morphological and physiological properties of the more important muscles have been described; 3) there is evidence for an interneuron l central pattern generator, and 4) specific motor neurons and interneurons have been identified. There have also been a few studies on afferent input; such studies are difficult to interpret since the techniques used, ablation and holding the limb rigid while manipulating the sense organ, can produce motor outputs which influence other receptors. This proposal present a new experimental technique whereby the main sensory leg nerve of one side of the body (right) is cut, crossed to the opposite side (left) and regenerates. The motor axons arise from somata within the CNS, regenerate via the crossed-nerve and innervate their contralaterally, left, homologous muscles (specific efferent innervation). The left sensory axons arise from the somata in the periphery, regenerate via the crossed-nerve and enter the right side of the CNS. We have preliminary evidence that afferent innervation is also specific since a monosynaptic reflex, which occurs in normal animals, is formed between left side afferents and right side efferents. This discovery opens an entirely new approach for the study of sensory influence on motor output because cross-innervated leg can be easily de-efferented leaving a purely sensory limb. The specific aims of this proposal are: to further study the specificity of the cross-innervation technique; to utilize this technique to gain insight to the possible role specific sense organs, e.g. hair-plates, campaniform sensillae, may play in the walking system. Standard electrophysiological recording techniques will be used.